Well, when I first started on my 82 truck I was getting less than 10mpg. My first move was to replace the 1945 Holley for a 1920 Holley. Which, you probably have already. I then started looking for a bigger carb. Found a Carter YF off of a 300 Ford six. It fit straight on and I only had to mess with the linkage. An air cleaner off a BBD fits nicely. I really liked that carb, it had a nice response. Plus, it had an electronic choke. Not like that choke on the 1945 or 1920. I do mostly city driving and was getting 10-11mpg. My best for this carb was 15mpg.

Early on when I was looking for different one barrels I had to change the PCV port. I have an aluminum intake and just above the EGR is a bolt. This bolt is plugging up a vacuum hole. I opened up the hole to accommodate a 3/8 inch connector. This is where I connected my PCV hose.

My next step was to get rid of the lean burn system. I found a dist. off of a 79 Dodge truck and bought a used Mallory coil and a reman. Mallory Hyfire ignition module for Mopar’s off Ebay. I bolted the ignition system to the inner fender on the dist. side of engine compartment. Hooking up the system wasn’t too bad. It took one wire from the voltage regulator to the coil + side and one wire from the module to the coil - side. Then, I hooked up the connection to the dist.
The dist. is where things get tricky. I tried to follow everyone’s advice on dialing in the dist., but I basically kept turning it until it started. Try starting at top dead center (TDC) and placing the rotor at #1 spark plug. After getting this together and adding an electric fan is when I started to see better mpg.

Then I started reading about the 5200 Holley/Weber. Better performance and mileage, I have to try that! This was a more complicated swap. I went and found a Vega 5210 progressive carb. It’s the same as the 5200, just the GM version. I did get an electric choke from a Pinto that fit. Found an adaptor at stove bolt that was a decent price.

The way I have my carb set on the intake manifold I had to cut about a 1/8 of an inch off the studs. This allowed the adaptor to sit flush on the intake manifold spacer. I used the throttle mechanism from the Vega to help me hook up the gas cable and the auto kick down. I have a 904 auto. If you have a stick it’s not as big of a deal. Just hook up the gas cable. Now I get 11-13mpg city.

I heard that there needs to be a change in the main jets from 180 to 170. This helps on fuel economy, meaning that the 180 jets are to big and run rich. I haven’t done this yet. I just rebuilt the carb to specs of the Vega, but I am planning on changing the jets to get better mpg.

The last big thing I need to do is the exhaust system. 2 ¼ inch pipe all the way back with a 2 ¼ inch turbo muffler. Anything bigger reduces torque. I do wonder if there is a difference if the exhaust came out before the rear wheel or after.

After I do the last two things on my list I think I should be around 15mpg city at least.

_________________

82 D150 Slant6 Shorty
http://www.cardomain.com/ride/658846

I get 12 or 13 mpg around town with a holley 2280 (from a 318) and no other modifications to the carb.(fits right on to a super six manifold with factory super six linkages from a volare) I've also got the heavier 727 trans, so it sounds like I should be feeling pretty good about that. I would love to get it into the 15 mpg range some day.

_________________
1980 Aspen 225 super six

That actually sounds real good! Especially with the 727 trans.

_________________

82 D150 Slant6 Shorty
http://www.cardomain.com/ride/658846